Former DSI chief Tarit Pengdith may have stolen the headlines this month after he received a one-year prison term for his role in the police station construction scandal. However, the team which he once headed handled a number of high-profile cases in 2018.
Though some suspects managed to escape and some cases require further work, the department's new chief, Paisit Wongmuang, has expressed his hope that further progress will be made in the year ahead.
1 Krungthai Bank loan saga rumbles on
Panthongtae "Oak" Shinawatra, son of fugitive former prime minister Thaksin Shinawatra, was allegedly involved in money-laundering linked with a Krungthai Bank (KTB) loan which was wrongfully granted to subsidiaries of Krisdamahanakorn real estate company during the Thaksin administration.
Another two suspects, Kanchanapa Honghern, secretary to the ex-wife of Thaksin, and her husband Wanchai, failed to meet public prosecutors on Oct 31 to hear indictment charges.
The couple was accused of receiving a 26-million-baht cheque tied to the KTB loan, worth a total of 9.9 billion baht.
While Mr Panthongtae reported to prosecutors and appeared in court to plead not guilty, Pol Col Paisit said Ms Kanchanapa and Mr Wanchai left for Hong Kong on Oct 5 and their whereabouts have been a mystery ever since.
The original loan was granted to Krisdamahanakorn though the firm was listed as a non-performing debtor and was not eligible to receive any more loans.
2 KCUC scandal probe widens
The DSI is expanding this investigation after finding there are likely to have been more suspects involved in money laundering in connection with the multi-billion-baht Klongchan Credit Union Cooperative scandal.
According to the DSI, some of the cases relate to the seizure of a globe-shaped building in Wat Phra Dhammakaya and the World Peace Valley building in the temple's meditation centre in Nakhon Ratchasima.
Parts of the money siphoned from the KCUC were donated to former temple abbot, Phra Dhammajayo, who was also indicted for laundering money and receiving stolen property in connection with the scandal.
The DSI has traced the money trails and managed to recover cash and assets worth 5.3 billion baht in total to the cooperative which then returned them to its more than 50,000 members.
However, the assets are only part of over 12 billion baht former KCUC chairman Supachai Srisupa-aksorn embezzled between 2009 and 2013.
Supachai was sentenced by the Criminal Court in 2016 to 16 years in jail after he pleaded guilty to charges of embezzlement, which he initially denied.
3 Trouble at Wat Phra Dhammakaya
Besides Phra Dhamnajayo, the DSI continues to probe irregularities concerning other monks and lay people managing the Khun Yay Maha Ratana Upasika Chandra Khonnokyoong Foundation, not to mention some well-known businessmen.
Many of them are suspected of handling money embezzled from the KCUC.
Among them are foundation president Wanna Jirakitti and its secretary Areepan Treeanusorn. Both are facing laundering charges.
Though Ms Wanna earlier presented evidence to prove her innocence, an initial DSI investigation found the accusation has grounds and she could not avoid a probe.
Some 30 monks in the Wat Phra Dhammakaya network were also found to have allegedly spent money buying shares in the stock market and acquiring plots of land.
The DSI is also investigating property tycoon Anant Asavabhokhin and his daughter, Alisa.
Supachai is suspected of using part of the embezzled money to buy eight parcels of land in Pathum Thani's Khlong Luang district which he resold to Ms Alisa for 298 million baht.
After the sale, Supachai did not return any money to the cooperative, the DSI investigators found.
Mr Anant was also accused by the DSI of laundering money through a land purchase scheme, in which land that was to be donated to Wat Phra Dhammakaya ended up under his ownership instead.
4 Rang Yen Resort encroachment
The DSI is digging deep into the acquisition of forest land in Loei's Dan Sai district and the construction of Rang Yen Resort on part of the area.
Relatives of construction tycoon Premchai Karnasuta were accused of being involved in the transactions.
Mr Premchai is also being investigated over poaching accusations at the Thungyai Naresuan wildlife sanctuary, a world heritage site in Kanchanaburi.
In the case of Rang Yen Resort, which is owned by PCK International Co, three company board members are relatives of Mr Premchai.
Investigators are expanding their probe to find out which year the suspects hatched their plan acquire unlawful land documents, the DSI chief said.
The Department of Land had already annulled the Nor Sor 3 Kor titles for the 147 plots on July 31, after it found that the titles were issued unlawfully.
An initial investigation found Sor Khor land occupancy documents from one place used to apply for land documents in another place about 20 years ago.
The DSI wants to know who was authorised by the company to buy the land.
So far the department has summoned more than 70 witnesses for questioning in order to find clues and evidence to act against suspects, including land officials.
5 Flesh trade at Victoria's Secret
Though former police chief Somyot Poompunmuang has now been cleared of involvement in suspicious money transactions with the owner of Victoria's Secret massage parlour, the DSI is pressing ahead with its probe into human trafficking allegations at the venue.
Kampol Wirathepsuporn, who ran the parlour, is believed to have fled to a neighbouring country after the Jan 12 raid on the parlour found 80 women, including girls from Myanmar, who had been working as prostitutes.
Among them were 14 girls aged under 18 years old.
The DSI is pressing on despite currently having no idea of Mr Kampol's whereabouts.
The DSI earlier suspected Mr Kampol might have tried to launder his assets by transferring them to others.
Pol Gen Somyot and Mr Kampol are known to have been friends.
The former police chief reportedly admitted he had borrowed 300 million baht from his "old friend", Mr Kampol, while he was a national police commander.
But he said the loan was settled and he had informed authorities of this transaction.
In September this year, the Criminal Court handed down jail sentences to six people involved in the prostitution of underage girls at the parlour. Inquiries are continuing.
